Navigation of aircraft



Sept. 30, 1930. H. JUNKERS NAVIGATION OF AIRCRAFT original Filed Jan.21, 1927 2 Sheets-Sheet l Original Filed Jan. 2l, 1927 2 Sheets-Sheet 2aircraft andhas particular reference to means Patented' sept. 3o, 1930UNITED STATES PATENT ori-lcs miao sumas, or DESSAU, GERMANY NAVIGATIONor AIRCRAFT riglnal application med January 21, 1987, Serial No.162,562, and in Germany January 21, 1926.' Divided and this applicationfiled Iarch 21, 1928. Serial No. 263,492.

This application is adivision of m copending application Ser. No.162,562, ed Jan. 21, 1927.

vMy inventlon refers to the navigation of for ascertaining during theflight of the craft the angle of deviation at any particular moment. l

s is well known to those skilled in the art it becomes frequentlynecessary to ascertain the angle of deviation of the craft, i. e. theangle enclosed between the longitudinal axis of the craft and thedirection of course above ground. The methods hitherto adopted for thispurpose require a direct observation of the displacement of ground as.compared with thecompass course, i. e.l with the position of thelongitudinal axis of the aircraft. This mode of observation is,Ihowever, disadvantageous in cases wherethe pilot himself is re Y quiredto effect the observation quickly and accurately, the pilotsl attentionbeing taken up with the maintainance of equilibrium and the observationof other instruments.

According to this invention the angle of deviation is ascertained in aparticularly advantageous manner, a direct observation of thedisplacement of ground relative to the compass course being dispensedwithby exposing to light during a certain time a sensitive layer of-material which has a predetermined position relative to thelongitudinal axis of the craft, thereby producing an image alpositionto' read which embodies an arrangement of bands correspondin to thisJdarker or lighter' parts of lthe groun ,these bands allowingascertaining the angle of deviation. .i l

The pilot is thus' only required to release the shutter of therespective device, which may be a photographic camera and is now in noff the exposure in a short' space of time the angle of deviationwithout y the other observations beingin any way disturbed thereby. f L

In order to further .facilitate the measuring of the angle, I may forinstanceL rovide a camera, the optical axisof which is irectedvertically towards the ground, and a dark slide containing a pileof-sensitized sheets of papeij, the lowermost of which is )early to beexposed and can be withdrawn or, after open-4 ing the dark slide, can betorn of after exposure, whereupon the camera admits at once of anothermeasurement without it being necessary -to insert a fresh sheet ofsensitized paper in the camera. The angle of deviation can now be readoff directly from.. the exposedsheet for instance by means of agraduation printed on the sheet itself or, by means of separate devices,for instance a grate of parallel lines adapted to be secure above theexposed sheet which is mounted on a carrier in a predetermined position,the grate being adapted to be rotated and being adjusted in parallel tothe'bands shown on the sheet, whereupon the angle of deviation can beread olf a scale. l

No fixation of the sensitized layer is required as the reading can beeected very quickly. The new lrocess involves the particular advantageof) being independent from momentous deviations of the course of thecraft, which would for instance disturb the ground, but do not play anyrole in the present case in view of the compensating effect of theexposure extending over a longer space of time. 1 Y' In the drawingsailixed to this specification and forming part thereof, means embodyingmy `invention are 'illustrated dia grannnatically by way of example.

In the' drawings, y Figs. 1-11 illustrate a particularly advantageousmanner of ascertaining the angles of deviation,

" Fig. 1 being a'plan view of an aircraft,

Fig. v2 a similar view of part of the ground, Fig. 3 a triangle ofvelocity, Fig..4 part of a photographic image, Fig.5 is'a side view `ofva photographic camera with the dark slide and sensitive layer" at rightanglesv to their normal position,

Fig. 6 being a. longitudinalsection thereof, r`.`Fig." is aside viewshowing the parts in normal position, T

Fig. 8.- shows a photogra hic card with figures and angles printed tereon,

l Figs. 9 and 10 are a plan view and crosssection, respectively, of anangle-measuring instrument and Fig. 11 is a plan view of another form ofsuch instrument.

At the moment where the angle of deviation shall be measured, the craft17 'shown in Fig. 1 may be assumed to travel above the groundillustrated in Fig. 2, which is characterized substantially by a wood18, fields 19 and a village 20. The longitudinal axis 21' of the craftmay be assumed topoint in the direction y, the actual course having, inconsequence of sidewind w (in Fig. 3), the direction .2.' The groundwill therefore be displaced relative to the craft in the direction ofthe arrows (Fig. parallel to 2.

n the craft is now mounted a photographic camera 22 in such manner thatthe main axis of light and thel longitudinal edges of the image extendin parallel to the longitudinal axis 21 of the craft. If, whentravelling over the ground shown in Fig. 2, a layer sensitive to lightis exposed for a short time, for instance during IAQ-1 minute in thiscamera, then, provided that the sensitivity to light is chosen inaccordance to the intensity effexposure, there will appear on thesensitive layer, as shown in Fig. 4, a lighter band h corresponding tothe dark wood 18 and at some .distance a darker band c corresponding tothe village 20, the direction of which encloses with the lateral edgesm,n of the layer, whichtare parallel-to the longitudinal axis 21 of thecraft, the angle of deviation al, which can now be easily read off, forinstance by means of an angle-measuring device.

A camera such as can be used for producing such images is illustrated inFigs. and 7 The camera 30 here shown is provided with a hinged darkslide 40 containing a block of sensitive paper. When the dark slide isin raised position, as is shown in Fig. 6, the angle of deviation canalso be observed directly, for instance by means of a ground glass frameplaced in the plane of image.

'Ihe angle can be read from the exposed phow t tograph eitherin theposition of the dark slide shown in the drawing or after withdrawing ortearing off the respective piece 0f paper.

In order to facilitate the ymeasuring of angle, I can provide an angulargraduation printed on the marginal portion of the card f or paper, asshown in Fig. 8. For the purpose of measuring the angle I merely place arule 41 (shown in dotted lines) onto the card in such manner that itsedge 24 extends across the centre 00 of the card and in parallel to thebands. The angle al can now be read of directly from the graduationbetween the main axis 21 of the card and the edge 24 of the rule. Theangular graduation can, however, also be provided on a separate framesurrounding the card or`on the frame 43 of the dark slide 40.

In the instrument illustrated in Figs. 9 and 10 the exposed card 60 isplaced on a plate provided with a circular scale, its main axisextending across the zero points of the scale. Above the plate and the photogram is mounted for rotation a disc 76 with marks 71. and carrying agrid of parallel links. These links are now adjusted in parallel to thebands on the photogram by turning the disc 76 and the marks 71 nowindicate the angle of deviation al' on the circular scale.

The instrument shown in Fig. 11 is provided with a fixed ledge 80, amovable led e 8l and a number of parallel links 82 exten ing from one-tothe other ledge, the grid of links thus formed being mounted above thephotogram, which is held in position by an abutment 83. The links 82 areadjusted in parallel to the bands visible on the photogram. An extension84 of one of the links 82 cooperates after the manner of a pointer withthe circular scale 85.

I wish it to be understood that I do not desire to be limited to theexact details of construction shown `and described for obviousmodications will occur to a person skilled in the art.

I claim z- Method for ascertaining from a flying aircraft the angleenclosed between the longitudinal axis of the craft and the direction ofcourse above ground, comprising making a time exposure of the ground ona sensitive layer ixed on the craft with one edge in a predeterminedposition relative to the longitudinal axis of the craft, therebyproducing an image which embodies an arrangement of bands correspondingto the darker and lighter parts of the ground, respectively, andmeasuring the angle enclosed between said bands yand said edge.

In testimony whereof I affix my signature.

HUGO J UN KERS.

